uniq 记录下

uniq - report or omit repeated lines

默认只输出不重复的行（相当于去掉重复的行）

[useputty_login@PC_IN_LAN ~]$cat a
boy took bat home
boy took bat home
girl took bat home
dog brought hat home
dog brought hat home
dog brought hat home

[useputty_login@PC_IN_LAN ~]$uniq a
boy took bat home
girl took bat home
dog brought hat home

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

-c 选项在行前面打印数字表示该行在文件中出现几次（重复几次）

[useputty_login@PC_IN_LAN ~]$uniq -c a
      2 boy took bat home
      1 girl took bat home
      3 dog brought hat home

-d 只输出重复的行（输出一行）

[useputty_login@PC_IN_LAN ~]$uniq -d -c  a
      2 boy took bat home
      3 dog brought hat home

-D 输出重复行的全部行

[useputty_login@PC_IN_LAN ~]$uniq -D  a
boy took bat home
boy took bat home
dog brought hat home
dog brought hat home
dog brought hat home

-u 只打印出现过一次的行

[useputty_login@PC_IN_LAN ~]$uniq -u  a
girl took bat home

-f N 忽略前N个域
a 23 45 23 45 34 36 23 45
b 23 45 23 45 34 36 23 45
c 23 53 23 56 23 45 67 23

把相同的行找出来 打印 如:

a 23 45 23 45 34 36 23 45
b 23 45 23 45 34 36 23 45

[useputty_login@PC_IN_LAN ~]$uniq -f 1 -D a
a 23 45 23 45 34 36 23 45
b 23 45 23 45 34 36 23 45
表示忽略第一个域 并打出所有重复行

[useputty_login@PC_IN_LAN ~]$uniq -f 2 -D a
a c 23 45 23 45 34 36 23 45
b d 23 45 23 45 34 36 23 45

从这可以看出是忽略第N个域前的所有域。

-c 与 -f 一样只是忽略的是第N个字符前面的所有字符。